From this reading, I get to know that the writing process instructional model has beeing evolving. When it's first put forward as a pedagogical approach, it emphasized on teachers' role of facilitator and the writing process as a "natural process mode" with the focus on the process instead of the products. As the model evolved, more attention began to be attached to the significance of teachers' directions. In recent years, this model stresses the explicit teaching of writing strategies with the belief that students can be nurtured to be writers with instructions. The writing process model has evolved from a simple linear formula to a complex recursive process.
The writing process model will change the attitudes of both teachers and students toward writing. With the strategies in mind, teachers feel more confident and supported to teach writing. With the instructions, the students will internalize a repertoire of process writing strategies and be more confident in writing.
The writing process model is beneficial, but few researches can prove exactly how much positive impact it has on students' writing products. Writing process is a complex phenomenon that includes not only procedural strategies but also other strategies do develop specific schemata. I believe there is no fix model for teaching writing, because our teaching should evolve with the changes of the students and the environment.